C70 ‘05 reverse wiring route and colours

[Shug]

Hi all,

Currently fitting a double din dab head unit, has reverse camera input and signal control wire, where is the route with easier access to rear for me to hook up to the reverse wire for the reverse lights, or does it ground through the switch? I hope it’s +12v when lights get turned on.

I already have a cctv system in car, but now swapping over to dash cam with front and rear, so using my existing rear camera for reversing and trailer hook up.

Thanks.